"Do you know how to weld?" I asked him when we met recently in Ann Arbor to discuss the project.
"I do now."
A solar farm, whose sole purpose is to soak up much sun energy as possible, loses out if its panels remain locked in a fixed position. The sky position of the sun varies throughout the year, and moving the panels periodically is essential to efficient systems. Unfortunately, when Field decided to build his own solar farm, he couldn't get a moveable "tracker" system for anything that was "close to reasonable"—so he built one himself. Even with the startup costs of equipping his own fabrication plant, the do-it-yourself approach was so much cheaper that it looked like a necessity if his project was to break even.
Field's trackers are simple steel structures with a hinged mechanism that allows the panel to be unlatched and then tilted into several specific angles based on time of year; the design is based on research from federal renewable energy studies. Field's two acre parcel of land—just off I-94 beyond a Target distribution center in rural Michigan—can have all its panels moved by 2 people in just 30 minutes. The setup was 8-10 percent more efficient than a fixed solar array, and when built was one of the most efficient large array systems in the state.
This wasn't a project installed by a major corporation; indeed, what's most remarkable about the solar farm is that Field is still a student studying both economics and electrical engineering at the University of Michigan. When we met, he had just come from a final exam.
Solar power isn't just for Arizona
Long interested in renewable energy, Field entered the university as an economics major and began researching energy projects in his spare time. “I went through a series of very bad ideas,” he said, before coming to the conclusion that “building wind generation infrastructure in Michigan is a terrible idea.”
But solar didn't look so bad. While it's true that sunny states like Arizona capture the public's imagination when it comes to solar, Midwestern states like Michigan can be workable. Arizona gets two-thirds more sun than Michigan's average of four usable hours of sun per day. But Arizona is also significantly warmer than Michigan, and most solar panels are significantly limited by heat. On Field's own solar farm, the effect is easy to see. His monitoring equipment shows that, on an 80 degree day, his panels drop to 75 precent efficiency and decay from there as the temperature rises.
Thanks largely to this temperature affect, Field's farm produces more power in the spring than in the summer. The total solar array can produce a maximum of 149kW, enough to power a couple hundred homes, but it never exceeds 130kW in summer thanks to the temperature effect and to the higher summer humidity (which scatters the light).
Field had a simple goal with the farm—“not to lose money on the first project"—and added that he's “not interested in proving that solar's not economically viable." Losing money on renewable power is simple; it's turning a profit that's hard.
And Field wants to show that renewable tech, even on this scale, can be profitable. To do so, he partnered with his father (a lawyer) and with a family friend who owned 250 acres of land outside Battle Creek. To reduce risk on the project, the team negotiated a 12-year fixed rate for their power from the local electric company Consumer's Energy. (Making that deal was made easier by a state guideline that 10 percent of power come from renewable sources by 2015, and by a Consumer's Energy feed-in tariff program for arrays up to 150kW.) The panels have a rated life of 25 years (after which they should still produce electricity at 80 percent of their initial efficiency), so calculating a break-even date was straightforward.
The challenge came in upfront construction costs when it became clear that a moveable commercial tracker system was simply too expensive. Field's decision to build the entire set of support structures with his father shaved costs significantly, but the team still had to bring in an electrical contractor ($80,000), purchase the panels from Evergreen Solar, buy the electrical inverters that make the panel power compatible with the electrical grid, set up their small factory, and get structural engineers to look at overall site designs and at the concrete footings used to hold the arrays.
An interview with Sam Field, Connor's father
Field and his father coordinated all this work and were on-site watching most of it get done. The idea wasn't just to save money; it was to get a crash course in all the necessary disciplines associated with large-scale renewable power projects.
“The goal was to learn how to do it,” said Field, and the numerous mistakes the team made were dubbed "tuition moments."
In the end, it all worked as planned, and the solar farm now nearly runs itself. As we talked, Field pulled out his iPhone and showed me the farm's realtime power generation stats, which are pulled directly from the inverters and available over the Internet. Combined with perimeter security system and some live-feed Internet video cameras, Field can keep an eye on the team's investment from an Ann Arbor classroom without having to run back constantly to check that everything is functioning properly.
Problems cropped up, of course. Nearby lightning strikes blew out fuses at the farm, while the light beams on the security perimeter failed (twice) without any apparent reason.
But the most serious issue came from the taxman. After installation of the solar farm on its two acres of land, the local tax assessor upgraded the site from "leasehold improvement" to "real commercial property"—and property taxes went up dramatically. The team believes the designation is improper, and the legal expertise of Field's father has proven helpful as the decision is appealed.
The project was designed to break even in 12 years, but the higher tax rates could throw off that calculation. Field has learned his lesson from the tax scrap; his new projects now get "prenegotiated" tax rates from local townships to avoid these kinds of unexpected surprises, and he's found that most towns welcome well-thought-out, financially viable renewable power projects.
Now that the key lessons have been learned, Field is forging ahead with several more ventures, though he's hesitant to say too much about them yet. One hint: they will all be significantly larger than the solar farm, which required electrical service work that could serve a much larger project for the same amount of investment. Motorized panel tracking systems have dropped dramatically in price, and Field plans to buy in bulk for future projects, so hot summers of welding are behind him.
Indeed, Field is spending this summer interning with a University of Michigan project researching new solar technology. He's also developing future projects of his own, including one that should get under construction by summer's end. Not bad for an undergrad.
Despite the hard work involved, Field has some simple advice for anyone who might follow his lead: "Do it."
SOURCE: http://arstechnica.com/gadgets/news/2011/08/how-one-michigan-undergrad-built-a-150kw-solar-farm.ars
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